E-M1 high ISO dark pixel noise in JPGs?

Discussion in 'Olympus Cameras' started by jurgen, Jan 27, 2014.

  1. jurgen

    jurgen Mu-43 Regular

    Jan 27, 2014
    Hi all!

    I've got a new E-M1, which I really really like, but I'm curious about some ISO 6400 jpg results I'm getting.

    I have noticed while pixel peeping that at 6400, my JPGS get the an occasional "dark" bundle of pixels (2x2) in certain areas of the frame.

    Here's a 300% crop of my dog, probably the easiest way to see it: http://imgur.com/oll7sU3

    And then here's a 100% of a very dark corner of the frame: http://imgur.com/0gMNuGa

    A 200% from a different snap: http://imgur.com/hb3XRIU

    Is this "normal" noise for ISO 6400? It does not show up in the RAW files, which makes me think that it's a result of the JPG engine. JPG quality is set to super fine and NR is set to low. Upping NR seems not to have an effect.

    Again, this is pixel peeping at it's worst, but I'm wondering if it's normal behavior. For what it's worth, the pixels are not pure #000000 black - they range from gray to black to (occasionally) deep navy blue.

    Can anyone provide me with some guidance?

    Thank you!

  2. phl0wtography

    phl0wtography Mu-43 Veteran

    Apr 15, 2011
    Since it doesn't show up in RAW, my educated guess would be, that it's a combined result of jpeg compression, and the algorithm applied in-camera to reduce noise.
    Unless you get the same clustered black pixels in a photograph of a uniformly coloured, and lit (yet dark) area, everything's fine, I'd say.
  3. jurgen

    jurgen Mu-43 Regular

    Jan 27, 2014
    They aren't uniformly distributed across all pictures, if that's what you mean (they don't show up in the same spot always.)

    Shooting the red wall in my apartment, I get this (which, to my novice eye, looks like what standard jpg compression should probably look like at 300% crop on an M43 camera at ISO 6400? I think?):


    The raw crop of the same area, for comparison (no noise reduction or processing, obviously):


    I have a feeling this is much ado about nothing, and that when I find this thread in a year I'll be embarrassed to have posted it. But I figured it better to ask, just in case.
  4. phl0wtography

    phl0wtography Mu-43 Veteran

    Apr 15, 2011
    Yes, that's what's to be expected from a m4/3 sensor at ISO6400. Perfectly normal.
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